1. Field of the Invention
The present invention pertains to an excavating bucket or dipper having lightweight fabricated top and bottom sections which are separable for replacement when damaged or worn out.
2. Background
Excavating shovel dippers or buckets must have adequate strength to withstand the high forces exerted thereon during excavation operations and be able to resist abrasive wear by the material being excavated. At the same time, it is important to minimize the mass of the dipper structure so that the payload capacity of the operating machine is not compromised or reduced by the weight of the dipper itself.
My U.S. Pat. No. 4,939,855, assigned to Atlantic Richfield Company, describes one method and arrangement of an excavating bucket or dipper wherein the heavy cast or fabricated structures of the prior art are modified to include a lightweight replaceable lower or bottom section. However, there has been a need to develop a lighter weight dipper structure which also includes replaceable upper and lower sections so that the lower section of the dipper, in particular, which is subject to high wear rates, may be replaced without requiring replacement of the upper or top section. Alternatively, of course, it may be desirable to replace the upper or top section before replacement of the bottom section. The reduction in dipper weight without sacrificing strength and durability has presented certain problems in dipper design which are solved by the unique, lightweight dipper according to the present invention.